High-frequency oscillating circuits



April 23, 1929. H. B. HOLTHOUSE 1,710,541

HIGH FREQUENCY OSCILLATINGCIRCUITS Filed Feb. 11, 1924- 2 Sheets-Sheet l Harry Elia/22201255. 3% f. M an April 23, 19.29. H. B. HOLTHOUSE 1,710,541

HIGH FREQUENCY OSCILLATING CIRCUITS Filed Feb. 11, 1924 2 Sheets-Sheet 2 Ha/"ry 51727222701155. 332M W a Patented Apr. 23, 1929.

' UNITED STATES HARRY B. HOLTI-IOUSE,

OF CHICAGO, ILLINOIS.

HIGH-FREQUENCY OSCILLATING CIRCUIT S.

Application filed February 11, 1924. Serial No. 692,053. I

My invention relates to high frequency oscillating circuits and has to do more particu larly with circuits of this character adapted for use in ignition circuits or for the excita- 6 tion of X-ray tubes, vacuum electrodes, ultra violet ray generation, etc.

An object of my invention is the provision of an improved circuit of the above character having certain advantages in construction and operation and which will be more. particularly referred to in the ensuing part of the specification and appended claims. Generally speaking, my present invention is an improvement over that shown inmy copending application for high tension circuit, Se-

rial Number 57 5,211, filed July 15, 1922 now Patent No. 1,624,951, April 19, 1927.

For a better understandingof myinvention, reference is to be had to the accom 0 panying drawings, in which- Fig. 1 illustrates diagrammatically one form of my invention adapted to be excited by any one of a number of different kinds of current;

Fig. 2 is a diagrammatic view of a circuit similarto that of Fig. 1, but illustrating one method of winding the oscillation transformer;

Fig. 3 shows my invention applied to an ignition system for internal combustion engines having transformers individual to the spark plugs;

Fig. 4 shows my invention applied to an internal combustion engine having a common transformer; and I Fig. 5 illustrates diagrammatically a spark gap adjustable relative to the circuit wave to vary the time of discharge; and

Fig. 6 is an end view of Fig. 5.

Referring now more in detail to the circuit of Fig. 1, I have shown a high frequency oscillating circuit which is adapted to be supplied with any suitable sort of exciting current and for purpose of illustration I show a number of such kinds of current. At A I have indicated a magneto, and I also show a magneto B supplied with timer contacts indicating that the magneto may be used as .at A or as at B, the timer contact beingoptional. I also show a generator at C of the permanent field type, a transformer D which may be connected to a suitable source, and a battery at E. Thus. any of such sources may be used for exciting the circuit. Also an arrangement having a primary oscillating circuit including a condenser 6, to the terminals of which the exciting current is connected, a spark gap 7, a primary winding 8 of an oscillation transformer OT, all in series and connected across the terminals of a condenser 9 which is also in series with the elements of the secondary oscillating circuit, which includes the secondary winding 10 of the transformer and a discharge element 11 indicated by a pair of points which may be the sparking points of a spark plug or any other device to which the circuit is applied. The various elements comprising the circuit are constructed, of course, according to the results desired and the spark gap 7 may be of any suitable type and may be of the r0- tary, stationary or quenched spark type, and preferably adjustable. preferably placed in series with the other elements of the primary oscillating circuit, and not necessarily confined to the particular point in the circuit illustrated.

In the preferred form of my invention, however, I preferably connect the exciting source across the terminals of the primary condenser 6 and connect the second condenser .9 so as to be common to the primary and sec ondary oscillating circuits and in multiple therewith. Also this second condenser as 9 is so connected that it is common to both pri-- mary and secondary windings of the oscillatlon transformer, allowing either or both to act as the necessary inductance in series with 'winding' 10 of the oscillation transformer,

which is preferably of a greater number of turns than the primary winding and thereby This spark gap 1s producing a potential in the secondary oscillating circuit greater than the primary circuit. This secondary oscillation circuit includes the elements 9, 10 and 11 in series, but the potential thereof is preferably greater than that of the primary circuit, being determined among other'things by the ratio of windings 8 and 10.

In using the oscillation circuit of Fig. 1 for ignition purposes and when excited by current from a magneto as at A, it has certain advantages among which is automatic electrical timing varying with the speed of the engine or piston. That is, as the engine,

and therefore the generator also, slows down and the piston speed reduces, the beginning of the ignition oscillations is retarded. Conversely, as the engine speed increases, the spark is advanced.

This automatic electrical timing is brought about by the adjustable spark gap 7 and the characteristics of the exciting source as, for example, assuming the use of a magneto in which the voltage curve is substantially a sine wave and in which the electrodes of the s ark gap are adjusted to start the current ow thereover at a predetermined potential which must be reached before the oscillations take place in the primary circuit. In such a magneto the voltage may depend upon the speed of the machine and the density of the field. The waveform is, of course, substantially the same for all speeds, but the maximum voltage varies with the speed. Thus with the magneto running with the engine, the voltage increases and decreases with an increase and decrease of the speed of the en-. gine. Accordingly, the point in the voltage wave at which the current jumps the spark gap 7 is earlier at a high speed than at a lower speed. Assuming, for example, that the spark gap 7 is adjusted to start the oscillations at a predetermined potential of 200 volts, the apparatus is preferably so proportioned that this .voltage will be reached at full retard of the spark for ignition. We will assume that this is the voltage reached at the peak of the wave. Then as the engine and generator increase in speed, and of course increase in speed of piston travel, this 200 volt sparking oint will be reached at an earlier period In the wave, thus advancing the beginning of the oscillations or ignition period; The apparatus is referably so proportioned that a point of 11 advance is reached at the roper time for full advance of the spark or ignition. Thus, assuming that at 200 revolutions per minute a maximum potential of 200 volts is produced, with the speed increased to 1000 revolutions per minute, the potential may increase to 1000 volts. Thus, under the latter circumstances, the oscillations would begin at an earlier period because the 200 voltage breaking point of the spark gap 7 is reached at an earlier period in'the voltage Wave. With the generator running in synchronism with the engine the charge will be fired at earlier points as the speed of the engine increases and later as the speed decreases.

It wlll thus be seen that I have provided automatic electrical timing when the circuit is used for ignition purposes.

In the above operation I have referred to a magneto generator, but it isto be understood that any suitable generator or alternator that produces a suitable wave form nlay be used to excite the circuit, providing the wave form be synchronized substantially with the piston speed of the engine.

If manual control of the timing is desired, a pair of timer contacts 12 may be provided operated by a cam as shown at generator B and the cam adjusted to var the period of making and breaking of t iese points 12 relative to the speed and position of the piston of the engine. Also such manual timing may be secured by manually varying the spark gap 7 so as to vary the time at which the current first jumps the gap and the oseillations commence.

In Fig. 2 I have shown the oscillating circuit of Fig. 1 with the magneto A connected thereto and showing the winding relation of the oscillation transformer OT. In Fig. 3 I have shown my invention applied to the ignition system of a four-cylinderinternal combustion engine in which an oscillation transformer OT is provided individual to each spark plug 11. In such case I preferably construct the spark plug and oscillation transformer as a single unit of the character shown in Fig. 4 of my copending application already referred to, Serial Number 575,211. In Fig. 3 a distributor F is shown arranged to successively operatively connect the spark plugs ll and corresponding oscillation transformer in circuit. I have shown the common condenser 9 as being grounded and the primary condenser 6 as grounded. Also the spark plugs 11 are shown grounded, but of course these maybe connected as indicated in Fig. 1, if desired.

In Fig. 4 I have shown my invention applied to a four-cylinder internal combustion engine in which a single oscillation transformer OT is used and the spark plugs properly associated by the distributor F.

If desired, a manual control of the advance and retard of this spark maybe provided by adjusting the time of operation of the spark gap relative to the current wave, or' travel of the engine piston, by a rotating spark gap of the character illustrated in Figs. 5 and 6. In this connection I show field or pole pieces 1516 and armature winding 17 .carried by the shaft 18. An arm 19 is carried by the shaft 18 and carries gap electrodes 20 which rotate relative to the rotary-adjustable stationary electrodes 21. These electrodes 21 are carried by the arm 22 which is rotatably supported on the shaft bearing and which may be rocked back and forth manually to advance and retard the spark as desired. The rotatable elec-' applying my invention, I appreciate that other arrangements will readily occur to those skilled in the art, and therefore I do not desire to be limited to what is shown and described, but aim tocover all that which comes Within the spirit and scope of the appended claims What I claim as new and desire to secure by United States Letters Patent is:

1. In a high -?frequency oscillating circuit, a primary oscillation circuit including a condenser, a spark gap, the primary winding of an oscillation transformer and a second condenser in series, a secondary high frequency oscillation circuit including a discharge element, the secondary winding of the oscillation transformer and said second condenser in series, said second condenser being common to both circuits, and an exciting source connected across the terminals of the first condenser.

2. In a high fre uency oscillating circuit, a secondary high requency oscillation circuit including a condenser, a discharge element or spark points and a secondary inductance in series, and an exciting primary circuit connected directly across the terminals of the condenser for charging the secondary circuit.

3. In a high frequency oscillating-circuit, an oscillating transformer, a spark gap, a condenser, a discharge element or spark points, and circuit connections including all the above elements forming primary and secondary oscillation circuits having said condenser electrically common to both windings of the transformer to act as an inductance in series with the condenser and spark gap to provide a high frequency oscillation circuit. 4. In an ignition circuit for explosive engines of the character described, a source of current of substantialsine waveform and varying in voltage substantially proportionate to the speed of the generator thereof, a secondary high frequency or igniting circuit of high frequency oscillations and a primary spark gap in circuit with said source adjusted to automatically vary the timing of the sparking of the secondary circuit to advance and retard the same as the speed of the engine varies.

5. In an ignition circuit for explosive engines of the character described, a source of current of substantial sine wave form and varying in voltage with the speed of the generator thereof, a secondary or igniting circuit of high frequency oscillations, and a primary spark gap in circuit with said source adjusted to automatically vary. the timing of the sparking of the secondary circuit to advance and retard the same as the speed of the engine varies.

6. In an ignition circuit for explosive engines of the character described, a source of current of substantial sine wave form and varying in, voltage with the speed of the generator thereof, a secondary or igniting circuit of high frequency oscillations, a primary spark gap in circuit with said source adjusted to automatically vary the timing of the sparking of the secondary circuit to advance and retard the same as the speed of the engine varies, and manual means foratively traveling electrodes relatively adjustable to function earlier or later relative to the piston to retard and advance the sparking period.

8. In an ignition system for explosive en- I gines of the character described, a high frequency oscillating circuit including a 'primary spark gap having relative movable electrodes operating to function in synchronism with the engine piston, and means to vary the operation of the electrodes during operation of the engine to advance and retard the spark as the change in speed or load necessitates.

9. In a high frequency oscillating circuit, a source of E, M. F. a primary oscillating circuit including said source, a spark gap, a condenser and the primary winding of a transformer, a condenser connected across said circuit between said source and the balance of said equipment, and a secondary oscillating circuit including the same 'condense'Fas that connected in the primary HARRY B. HQLTHOUSE. 

